ML20211K152

TS Change 99-10 to Licenses DPR-77 & DPR-79,providing Clarification to Current TS Requirements for Containment Isolation Valves

ML20211K152
Person / Time
Site:	Sequoyah
Issue date:	08/30/1999
From:	Salas P TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20211K157	List: ML20211K152 ML20211K172
References
NUDOCS 9909070115
Download: ML20211K152 (12)

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• Tennessee Valley Atilhority Post Oftce Box 2000. Soddy-Daisy. Tennessee 37379 August 30, 1999 TVA-SQN-TS-99-10 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 Gentlemen:

In the Matter of ) Docket Nos. 50-327 Tennessee Valley Authority ) 50-328 SEQUOYAH NUCLEAR PLANT (SQN) - UNITS 1 AND 2 - TECHNICAL SPECIFICATION (TS) CHANGE NO. 99-10, " CONTAINMENT ISOLATION VALVES" In accordance with the provisions of 10 CFR 50.4 and 50.90, TVA is submitting a request for an amendment to SON's Licenses DPR-77 and 79 to change the TSs for Units 1 and 2.

The proposed change provides clarification to the current TS requirements for containment isolation valves.

The specifications are revised to relocate an existing surveillance requirement (SR) from TS 3.6.1.1, " Containment Integrity," to TS 3.6.3, Containment Isolation Valves. In addition, the action requirements of TS 3.6.3 are revised to provide clarification for two conditions that involve:

(1) a single inoperable containment isolation valve in a containment penetration flow path, and (2) two inoperable containment isolation valves in a penetration flow path.

Also included is a change to SR 4.6.3.2. The proposed change to SR 4.6.3.2 removes current mode limitations (i.e., cold shutdown or refueling mode) for testing automatic containment 1 solation valves to demonstrate valve operability.  ;

9909070115 990830 i PDR ADOCK 05000327 P PDR t

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U.'S. . Nuclear-Regulatory Commission

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. August 30, 1999 .

TVA.has determined that there are no significant hazards considerations associated.with the proposed change and that the change'is~ exempt from environmental review pursuant to the provisions of 10 CFR 51.22 (c) (9) . The SQN Plant Operations. Review-Committee and.the SQN Nuclear Safety Review Board'have reviewed this proposed change and determined that operation of SON Units 1 and 2, in accordance with the proposed change, will not endanger the health and safety of the public. Additionally, in accordance with 10 CFR 50. 91 (b) (1) , TVA is sending a copy of this letter to the~ Tennessee State Department of Public Health.

Enclosure.1 to'this' letter provides the description and evaluation of the~ proposed change. Enclosure 2 contains copies of the appropriate TS pages from Units 1 and 2 marked-up to show the proposed. change. Enclosure 3 forwards the revised TS pages for Units 1 and 2 which incorporate the proposed change.

TVA requests-that the revised TS be made effective within 45 days of NRC approval. If you have any questions about this change, please telephone me at (423) 843-7170 or J. D.

' Smith at' .(423) 843-6672.

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.-a as e Licensing and Industry Affairs Manager j

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My Commission Expires October 9, 2002 Enclosures cc: See Page 3  ;

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,. U.S. Nuclear Regulatory' Commission Page 3 i

, August 30, 1999 cc (Enclosures):

Mr. R. W. Hernan, Project Manager Nuclear Regulatory Commission One White Flint, North 11555.Rockville Pike Rockville, Maryland 20852-2739 Mr. Michael H. Mobley, Director (w/o Enclosures)

Division of Radiological Health Third Floor L&C Annex 401 Church Street Nashville, Tennessee 37243-1532 NRC Resident Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy-Daisy, Tennessee 37379-3624 Regional Administrator U.S. Nuclear Regulatory Commission Region II Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, Georgia 30303-3415 l

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l l ENCLOSURE 1 4

TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT (SQN)

UNITS 1 AND 2 DOCKET NOS. 327 AND 328  !

PROPOSED TECHNICAL SPECIFICATION (TS) CHANGE 99-10 DESCRIPTION AND EVALUATION OF THE PROPOSED CHANGE l I. DESCRIPTION OF THE PROPOSED CHANGE l

TVA proposes a revision to SON TS 3.6.1.1, " Containment l l Integrity," to relocate Surveillance Requirement (SR) l 4.6.1.1.a. The following provides SON's current SR 4.6.1.1.a. and a related fnntnote to SR 4.6.1.1.a.

"4.6.1.1 Primary CONTAINMENT INTEGRITY shall be demonstrated:

a. At least once per 31 days by verifying that all penetrations

• not capable of being closed by OPERABLE containment automatic isolation valves and required to be closed during accident l

conditions are closed by valves, blind flanges, or deactivated automatic valves secured in their positions, except for valves that are open under administrative control as permitted by Specification 3.6.3.

l *Except valves, blind flanges, and deactivated automatic valves which are located inside the annulus or containment !

or the mainsteam valve vaults and are locked, sealed or otherwise secured in the closed position. These penetrations shall be verified closed during each COLD l SHUTDONN except that such verification need not be l performed more often than once per 92 days."  !

l TVA's proposed change relocates the above SR, along with the associated footnote, to SON TS 3.6.3, " Containment Isolation Valves." The following SR language is not included with the proposed relocation and is deleted:

"as permitted by Specification 3.6.3."

TVA further proposes a revision to SON TS 3.6.3, j " Containment Isolation Valves." The proposed change is a l

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! TS improvement that provides. clarification to the current

. Action (a) requirement. Action (a) currently states:  !

"a) With one or more of the isolation valve (s), except

l. containment vacuum relief isolation valve (s),

inoperable, maintain at least one isolation valve l OPERABLE in each affected penetration that is open and either:

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1. Restore 'the inoperable valve (s) to OPERABLE status within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, or 4 2.nIsolate each affected penetration within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> by use of at least one deactivated automatic valve '

secured in the isolation ~ position, or

3. Isolate each affected penetration within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> by f '

l use of at least one closed manual valve or blincI flange; or

4. Be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />."

TVA's proposed change' modifies Action (a) to read as follows:

"a. With one or more penetration flow paths with one containment isolation valve inoperable; except for containment vacuum relief isolation valve (s), isolate each affected penetration within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> by use of at

.least one closed deactivated automatic valve, closed manual valve, blind. flange, or check valve with flow through the valve secured; and, verify' the affected penetration flow path is isolated once per 31 days for isolation devices-outside containment, and prior to entering MODE 4 from MODE 5 if not performed within the previous 92 days for isolation devices inside containment."

The proposed Action (a) addresses a condition for isolating a penetration flow path with a single inoperable containment isolation valve. The stated exception for containment vacuum relief isolation valves is specific to SON TSs'and the special requirements associated with these valves [ refer to the current Action (c) of SON TS 3.6.3).

A new provision is introduced to SON TSs that allows a containment penetration flow path to be isolated by means

of a " check valve with flow through the valve secured." A second new provision that is introduced requires the affected penetration flow path be verified.as isolated once per 31' days for isolation devices outside containment and

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prior to entering Mode 4.from Mode 5 if not performed within the. previous 92 days for isolation devices inside containment.

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, Current shutdown requirements from Action (a) are relocated to a new shutdown action [see new Action (d)].

I A new Action (b) is proposed as follows: l 1

"b. With one or more penetration flow paths with two )

containment isolation valves inoperable; except for containment vacuum relief isolation valve (s), isolate each affected penetration within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> by use of at least one closed and deactivated automatic valve, closed manual valve, or blind flange, and verify' the affected penetration flow path is isolated once per 31 days."

TVA's newly proposed Action (b) addresses a condition involving two containment isolation valves inoperable in a penetration flow path. This action requires 1solating the affected penetration within one hour through the use of at least one closed and deactivated automatic valve, closed manual valve or blind flange. Affected penetration flow paths must be verified as isolated once per 31 days for isolation devices outside containment and prior to entering Mode 4 from Mode 5 if not performed within the previous 92 days for isolation devices inside containment.

The current Action (b) is relabeled Action (c). The requirements of this action remain essentially unchanged with the exception that shutdown requirements are relocated to a new ACTION (d).

Two nt4 footnotes are introduced in association with the proposed Actions (a) and (b). The first footnote states:

" Isolation devices in high radiation areas may be verified by use of administrative means."

The second footnote states:

" Isolation devices that are locked, sealed, or otherwise secured may be verified by use of administrative means."

These footnotes provide administrative controls for verifying every 31 days that isolation devices are in their proper position.

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Action (d) is a newly proposed action that provides unit I

. -shutdown requirements-when Actions (a), (b), or (c ) can not be satisfied. The new Action (d) states:

t "With any of the above ACTIONS not met, be in at least HOT

[ STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />."

A change is proposed to SR 4.6.3.2. The current SR 4.6.3.2 reads as follows:

"4.6.3.2 Each automatic containment isolation valve shall be demonstrated OPERABLE during the COLD SHUTDOWN or REFUELING MODE at least once per 18 months by:"

TVA's proposed change to SR 4.6.3.2 removes current mode

-limitations by deleting the words "during the COLD SHUTDOWN or REFUELING MODE."

A bases change is provided in association with the change to' Action (a) to clarify one of the methods provided in the action for isolating a penetration flow path (i . e . , check valve with flow through the valve secured).

II. REASON FOR THE PROPOSED CHANGE The purpose of the proposed relocation of SR 4.6.1.1.a is )

to group SRs associated with the containment isolation function into SON's containment. isolation valve TS (TS 3. 6.3) . I The purpose of the proposed change to the action requirements of TS 3.6.3 is to clarify current action requirements associated with an inoperable containment

. isolation valve (s) . The language of SON's current action

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requirements is ambiguous with respect to the allowed number of inoperable containment isolation valves in a penetration flow path. ,

l The purpose of TVA's proposed change to SR 4.6.3.2 is to remove a mode limitation (i.e., cold shutdown or refueling mode). Compliance with this mode limitation would limit testing to these modes and would not provide flexibility I for performing the surveillance while the unit is defueled (i.e., no mode).

III. SAFETY ANALYSIS

Background:

SON's containment isolation valves form part of the containment pressure boundary and are typically arranged El-4

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with two isolation barriers that are closed on a

. containment isolation signal. These isolation devices are either passive:or active (automatic). Manual valves, de-activated automatic valves secured in their closed position (including ' check valves with flow through the valve secured), blind flanges,.and closed systems are considered j passive devices. Check valves, or other automatic valves designed to close without operator action following an accident, are considered active devices. Two barriers in series are provided-for each penetration so that no single credible failure or malfunction of an active component can i

result in a loss of isolation or leakage that exceeds limits assumed'in the safety analyses. One of these barriers may be a closed system. These barriers (typically containment ~ isolation valves) make up the Containment Isolation System.

The TS operability requirements for containment isolation valves help ensure that containment is isolated within the time limits assumed in the safety analyses. Therefore, the operability requirements provide assurance that the containment function assumed in the safety analyses will ne maintained.

Applicable Safety Analysis L ~ SON's containment isolation valve limiting condition for operation supports the safety analyses assumptions related to minimizing.the release of fission products from containment. As part of the containment boundary, containment isolation valve operability supports leak tightness of the containment. Therefore, the safety analyses of any event requiring isolation of containment is applicable to this LCO.

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The Design Basis Accident that results in a release of radioactive material within' containment is a loss of coolant accident. In the analysis for this accident, it is assumed that containment isolation valves are either closed or function to close within the required isolation time following event initiation. This ensures that potential paths to the environment through containment isolation valves are minimized.

Safety Impact:

The majority of the revisions proposed in this request do not alter the intent or application of the current TS requirements. The purpose of these revisions is to align TS requirements associated with containment isolation devices into SON's containment isolation valve TS and to eliminate ambiguity with regard to action requirements for El-5 t-

1 an inoperable containment isolation valve (s) . The pt ; posed revision also adds' flexibility to an SR that is overly restrictive. The-following discussions provide the specific impact for each proposed revision to TSs 3.6.1.1 and 3.6.3.

The'first revision is relocation of SR 4.6.1.1.a from SON TS 3.6.1.1, " Containment Integrity" to SON TS 3.6.3,

" Containment Isolation Valves." SR 4.6.1.1.a is a 31-day SR that ensures containment penetration flow paths are isolated. This is accomplished by visually verifying valves, blind flanges, or deactivated automatic valves are secured in the closed position. This SR ensures that the containment isolation function is satisfied. A comparison of the SON TSs and Westinghouse Electric Company standard TSs (NUREG-1431) indicates that SON's SR 4.6.1.1.a is associated with the containment. isolation function.

Containment integrity is fulfilled through SR 4.6.1.1.c and the reference to SON's Containment Leakage Rate Testing Program (SON TS 6.8.4.h). This program ensures containment leakage is maintained within 10 CFR 50, Appendix J limits.

Accordingly, TVA's proposed relocation of this surveillance is appropriate for consistency with NUREG-1431 and grouping of SRs that provide a containment isolation function.

The second revision is introduced in TS 3.6.3. The proposed Action (a) provides a new means of isolating a penetration flow path using a " check valve with flow through the valve secured." This method is consistent with ^

NUREG-1431 and is considered acceptable because it includes the use of at least one isolation barrier that cannot be adversely affected by a single active failure. One additional change to Action (a) includes the incorporation of a "once per 31 day" verification that ensures the affected penetration flow path is isolated. This verification is appropriate since the configuration of SON's valves are governed by administrative controls and the probability for misalignment is low.

The third revision is addition of a new Action (b). This action requires isolation of a penetration flow path within one hour when two containment isolation valves in the flow path are inoperable. This action and timeframe for isolation is consistent with the one-hour action i requirement of SON TS 3.6.1.1 for restoring containment integrity. Action (b) also incorporates the 31-day verification that ensures the affected penetration flow l path is isolated. i Two new footnotes are introduced with Action (a) and Action (b) that provide a level of flexibility for isolation devices and their location and condition. The El-6

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first footnote applies to isolation devices that are in

. high radiation areas. The footnote allows the devices to be verified closed using administrative means. Allowing verification ~by administrative means is considered acceptable, since access to these areas is typically restricted. Therefore, the probability of misalignment of these devices, once they have been verified to be in the proper position, is low. The second footnote (refer to TSTF-269, Revision 1) is similar to the first in that isolation ~ devices that are locked, sealed, or otherwise secured may be verified by use of administrative means.

This is based on the position that-devices that are secured have a low probability for misalignment.

A fourth revision removes mode limitations in an SR that tests the actuation signals associated with containment isolation valves. The current mode limitations are overly restrictive and would even preclude testing while the unit is defueled (no mode).

In addition to the above, editorial changes are introduced by the revision to Action (a). Action items have been arranged to accommodate the addition of the new Action (b) and shutdown action requirements have been relocated from the current actions to a new Action (d).

In conclusion, the proposed revisions described above remain consistent with requirements contained in NUREG-1431 and provide clear requirements within the SON TSs for containment isolation valves. These changes will continue to provide appropriate actions and surveillance requirements for demonstrating each containment isolation )

valve OPERABLE. These changes will not adversely impact l nuclear safety. I IV. NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION TVA has concluded that operation of SQN Units 1 and 2, in accordance with the proposed change to the technical specifications, does not involve a significant hazards consideration. TVA's conclusion is based on its '

evaluation, in accordance with 10 CFR 50. 91 (a) (1) , of the three standards set forth in 10 CFR 50.92(c).

A. The proposed amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated.

The proposed revisions enhance the technical specification (TS) requirements to provide greater consistency with the standard TS in NUREG-1431. This revision proposes changes to the requirements for El-7

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containment isolation valves in Specifications 3.6.3.

. A proposed revision relocates a surveillance

( requirement (SR) from SON TS 3.6.1.1, " Containment i

Integrity" to SON TS 3.6.3, " Containment Isolation l Valves." A proposed revision to TS 3.6.3, Action (a), a new Action (b), and a proposed revision 3 to SR 4.6.3.2 provide improvements to the existing TS l requirements. The proposed revisions are not the

! result of changes to plant equipment, system design, l testing methods, or operating practices. The modified ,

i requirements will allow some relaxation of current )

l action requirements, and SRs. These changes provide l more appropriate requirements in consideration of the

safety significance and the design capabilities of the plant as determined by the improved standard TS j industry effort. SQN TS 3.6.3, " Containment Isolation j

Valves," continues to provide controls to ensure these l valves isolate within the time limits assumed in the safety analyses. Operability of these valves continues to assure that the containment isolation l function assumed in the safety analyses is maintained.

l Since these proposed revisions will continue to l support the required safety functions without l modification of the plant features, the probability of l an accident is not increased.

The provisions proposed in this change request will continue to maintain an acceptable level of protection for the health and safety of the public and will not significantly impact the potential for the offsite i release cf radioactive products. The overall effect

" of the proposed change will result in specifications that have equivalent or improved requirements compared to existing specifications for containment isolation

! valve operability and will not significantly increase the consequences of an accident.

l l l l B. The proposed amendment does not create the possibility ;

l of a new or different kind of accident from any j l accident previously evaluated.

The proposed revisions are not the result of changes to plant equipment, system design, testing methods, or !

I operating practices. The modified requirements will allow some relaxation of current action requirements, and a SR consistent with NUREG-1431. These changes provide more appropriate requirements in consideration of the safety significance and the design capabilities of SON's containment isolation system. The specifications for containment isolation valves serve i to provide controls for maintaining the containment L pressure' boundary. TVA's proposed changes does not i

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I contribute to the generation of postulated accidents.

Since the function of the containment isolation valves and their associated systems remains unchanged, and the effects do not contribute to accident generation, the proposed changes will not create the possibility of a new or different kind of accident.

C. The proposed amendment does not involve a significant reduction in a margin of safety.

The proposed changes will not result in changes to system design or setpoints that are intended to ensure timely identification of plant conditions that could be precursors to accidents or potential degradation of accident mitigation systems. Operability requirements for SON's containment isolation valves remain unchanged. TVA's proposed revisions provide some relaxation and flexibility to existing actions and a SR; however, the addition of a new action requirement for a 31-day periodic verification of valve position provides conservative administrative controls to ensure containment isolation function is maintained.

The action times are acceptable considering the redundant features of containment penetration flow paths and the allowed time intervals that have been developed by the industry and NRC.

TVA's revisions will continue to provide the necessary actions to minimize the impact of inoperable containment isolation valves and will provide testing activities that will ensure containment isolation system operability. The setpoints and design features that support the margin of safety are unchanged and actions for inoperable systems continue to provide appropriate time limits and compensatory measures. Accordingly, the proposed changes will not significantly reduce the margin of safety.

V. ENVIRONMENTAL IMPACT CONSIDERATION The proposed change does not involve a significant hazards consideration, a significant change in the types of or significant increase in the amounts of any effluents that may be released offsite, or a significant increase in individual or cumulative occupational radiation exposure. Therefore, the proposed change meets the eligibility criteria for l categorical exclusion set forth in 10 CFR 51.22 (c) (9) .

Therefore, pursuant to 10 CFR 51.22 (b) , an environmental assessment of the proposed change is not required.

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